The present invention relates to a subcutaneous tunnelling device and methods for subcutaneous tunnelling useful for securing and sealing a catheter within the subcutaneous tissue of a patient.
In the medical field, there is often the need to form a subcutaneous tunnel within a patient. Ordinarily, such tunnels are used to secure a catheter or other tubular means inside the body of the patient. Catheters, shunts, drainage tubes and the like, generally referred to herein as catheters, may be located within various sections of the human body for the introduction and removal of fluid from the body.
It is known to use a trocar to create a subcutaneous tunnel and to subsequently use the trocar to pull a catheter through the formed tunnel. When using prior art trocars, which have a circular cross section, a subcutaneous tunnel is created which has a constant inner diameter approximately equal to the maximum outer diameter of the trocar. This inner diameter is intended to approximate the outside diameter of the catheter or other tubular member to be secured in the tunnel.
One common application of subcutaneous tunnels is for securing the proximal end of a catheter when the distal end of the catheter has been inserted into an area of the body, such as a vein. By securing the proximal end of the catheter in some manner, it protects the patient from having the catheter accidentally pulled from the vein. The tunnel is formed and the catheter is positioned in the tunnel, typically by attaching the catheter to one end of a trocar and pulling the catheter through the tunnel. Trocars typically include a piercing point at one end which is used to form the tunnel. The opposite end of the trocar has a single set of threads which are used to grip the interior surface of the catheter to enable the trocar to pull the catheter through the tunnel. To secure the proximal portion of the catheter in the subcutaneous tunnel, many catheters are provided with a fabric tissue ingrowth stabilizing cuff wrapped around a portion of the outside of the catheter which is to be located within the subcutaneous tunnel. The cuff is generally sized to fit snugly in the tunnel or other area. Once in place, the surrounding subcutaneous tissue grows into the cuff thereby sealing the tunnel and securing the proximal portion of the catheter so that it cannot be pulled out during use.
While such subcutaneous tunnelling procedures are effective, they still present some disadvantages. When tunnelling soft durometer catheters, for example, a single catheter of a Tesio catheter assembly, frictional forces created when pulling the large diameter stabilizing cuff through the narrow tunnel with the trocar are difficult to overcome. However, a snug fit is desired in order to seal the tunnel effectively. Occasionally, the proximal portion of such a catheter may snap at the location of the stabilizing cuff where the forces tend to be localized. In such an instance, the physician may have to re-catheterize the patient and remove the broken catheter.
Therefore, there is a need in the art for a method of tunnelling and a tunnelling device which achieves the advantages of the prior art procedures in achieving a snug fit and stabilizing the catheter, but which eliminates disadvantages encountered in tunnelling and placing catheters having such cuffs by reducing the effects of the frictional forces encountered during tunnelling when pulling the catheter and cuff through the tunnel.